Step-feed mechanism for machine-tools.



PATENTED MAY 23, 1905.

J. MILLS. STEP FEED MECHANISM FOR MACHINE TOOLS.

APPLICATION FILED DEC. 27. 1904.

511mm" for UNITED STATES Patented May 23, 1905.

PATENT OEEIcE.

JAMES MILLS, OF CINCINNATI, OHIO, ASSIGNOR OF ONE-HALF TO ALBERT S.SMITH, OF CINCINNATI, OHIO.

STEP-FEED MECHANISM FOR MACHINE-TOOLS.

SPECIFICATION forming part of Letters Patent No. 790,847, dated May 23,1905. Application filed December 27, 1904. Serial No. 238,333.

tween the reversible driving-shaft and a stepfeed mechanism, with a tripand stops adapted to automatically cut out such positive connection atintervals in the reverse rotations of the driving-shaft, there beingauxiliary light friction connection between the driving-shaft andstep-feed mechanism adapted to release the trip at the beginning of thereversal of the driving-shaft and to retain the trip in engagement withthe stop until the reversal of the driving-shaft.

While this invention is applicable to various forms of step-feed, itsprincipal utility is in connection with a shaper of the geared type, andit is accordingly so illustrated.

The chief object of this invention is to adapt a positive step-feedmechanism to the conventional feed mechanism of a shaper with as littleas possible of change, addition, or reorganization of parts.

The features of the invention are more fully set forth in thedescription of the accompanying drawings, forming a part of thisspecification, in which Figure 1 is a side elevation of a shaper. Fig. 2is a section, enlarged, on linear m, Fig. 1. Fig. 3 is an enlargedsectional view of the releasing mechanism of the power feed for thetable. Fig. 4 is an enlarged section on line w w, Fig. 2, illustratingthe stops for releasing the power in elevation.

1 represents the frame of the shaper.

2 represents the ram traversing gibbed ways upon the upper portion ofthe shaper. Said ram is provided with a rack, to which motion isimparted by the usual gearing, well known in shapers of this class, butnot shown in the drawings.

3 is the table to which the step-feed is to be imparted. It reciprocateshorizontally in ways on cross-head 3, which in turn may be reciprocatedon vertical ways l on the front portion of the frame 1.

5 represents a reversible driving-shaft, suitably journaled in hearingsin the frame 1 and projecting outwardly therefrom. 6 represents a gearfixed to said shaft and in mesh with a gear upon shaft 7, said shaft 7being provided with pulleys for transmitting a forward and reverserotation to the gear 6. (See Figs. 1 and 2.) This is accomplishedthrough the usual belt-reversing pulleys on driving-shaft 7. Thisreversing mechanism is not shown, as any well-known form may beemployed.

8 represents a gear integral with or fixed to gear 6, adapted to meshwith a gear on shaft 9, which gear in turn is in mesh with a rack of theram 2.

10 represents a sleeve loose upon shaft 5, provided with a flange 11 atone end thereof.

12 represents a plate fixed to the flange 11 of sleeve 10 by means ofbolts. This plate 12 is provided with a gibway 13, the center portion ofwhich is bored out and within which bore a feed-screw 14 is provided.

15 represents a slide-plate gibbed to plate 12 and provided with a nut16, having threaded engagement with screw 14 for adjusting theslide-plate upon the plate 12.

17 represents a connecting-rod pivotally connected to slide-plate 15 fortransmitting motion to the pawl-plate 18, journaled upon the cross-feedscrew of the cross-head 3.

19 represents a ratchet-wheel fixed to the cross-feed screw 20.

21 represents a pawl upon the pawl-plate 18, adapted to be engaged withthe ratchetwheel 19.

22 represents a sleeve fixed to the shaft 5 and provided with a flange23 and lying between the flange 11 of the sleeve 10 and the plate 12.

24 25 represent leather packing adapted to frictionally engage with theflange 11 and plate 12 for driving the same.

So much of the mechanism above described is common to the prior art. Inthe operation of such prior step-feed devices the connection between thereversible driving-shaft and the step-feed mechanism is the frictionelements described and shown between driving-shaft 5 and sleeve 10.Ashort step-feed is required, and hence it is necessary that sleeve 10shall only receive a part of the opposite rotations of shaft 5, so thatwith such prior devices positive stops are provided for the sleeve 10,which limits its rotation in opposite directions relative to theopposite rotations of shaft 5. It is evident that the friction must bepowerful enough to give the step-feed and that it must be weak enough toallow of constant slippage during the intervals at which the sleeve 10is held at rest when engaged with the opposite stops. In addition to thedisadvantages of a friction power feed the slippage is a wearing elementwhich constantly depreciates the strength of the feed. It requiresconstant adjustment and renewal and at that is a makeshift at best. Withmy invention I dispense with the element of a strong friction connectionfor the step-feed and substitute a positive connection or clutch betweenthe driving-shaft 5 and the sleeve 10, which trips to throw out thispositive clutch during the intervals at which the sleeve 10 is to remainstationary; but I retain an auxiliary light friction between thereversible driving-shaft 5 and the sleeve 10 sufficient to unshift thetrip at the moment the drivingshaft is reversed and sufficient to holdthe trip in position of engagement with the opposite stops during thesaid interval at which the sleeve 10 is stationary. I will now describethe features of novelty by which 1 preferably accomplish the saidresult.

From shaft 10 is projected a radial arm 26, the outer end of which isturned parallel with the shaft 5 and which turned end overhangs agear-wheel 27, keyed to shaft 5, as shown in Fig. 2. The bent end ofsaid arm 26 is provided with a tripping clutch-pin 28, the inner end ofwhich is adapted to engage into the teeth of gear-wheel 27, so as toform a positive connection or clutch between shaft 5 and sleeve 10. Thusit will be seen that the table 3 is given its step cross-feed by apositive power transmission.

29 represents a coil-spring seating within the bore of the arm 26 forimparting normal outward tension to the detent-pin 28.

30 represents a cam-plate fixed to the detent-pin 28, adapted to engagethe stops 31 32, adjustably mounted in lugs 33 34:, said lugs beingformed integral with the plate 33, said plate being secured to theframe 1. Thus as the cam-plate 30 engages either one of the stops itwill throw the tripping clutch-pin 28 out of engagement with the gear27, and thereby arrest the motion of sleeve 10 and cross-feed mechanismheretofore described in connection therewith.

Looking at Fig. 4, assume that gear-wheel 27 is moving in a direction tocarry pin 28 toward the stop 31, the cam on plate 30 just engaging theedge of the stop 31. The continued movement of pin 28 in that directionlifts clutch-pin 28 from engagement with gearwheel 27. The sleeve 10 isstopped. Hence the step -feed is cut out, while the shaft 5 and gear 27continue their rotation in said direction, the light friction permittingof the necessary slippage between shaft 5 and sleeve 10. This lightfriction is sufficient to hold the pin 28 at this extreme position ofmovement until the shaft 5 is reversed, when the friction will shiftsleeve 10 with shaft 5 in the oppo site direction of rotation,disengaging the plate 30 from the stop 31, so that the clutch-pin 28again engages into the teeth of gear-wheel 27 and the step-feedmechanism is positively actuated during the reverse drive of shaft 5until the plate 30 engages the opposite stop 32.

This mechanism is simple, readily attachable to conventional shapers ofthis class, and it effectually eradicates the friction power step-feed,with its attendant disadvantages. Thus it will be seen that I haveprovided a positive table step-feed for a shaper and adapted it to theestablished shaper organization in.

a very simple and effective manner.

Having described my invention, I claim In a shaper-table-feed mechanism,a reversible driving-shaft, a toothed wheel fixed to an intermediateportion thereof, a sleeve on the projecting end of said shaft, frictionconnections between the outer ends of said shaft and sleeve, acrank-disk on the outer end of the sleeve, connections between the saidcrank-disk and the table-feed mechanism, a pawl on the inner end of saidsleeve adapted to normally engage with said toothed wheel, andtripping-stops supported by the frame adapted to disengage said pawl atpredetermined intervals in the reverse rotation of the sleeve,substantially as described.

In testimony whereof I have hereunto set my hand.

JAMES MILLS.

WVitnesses:

OLIVER B. KAISER, LUISE BECK.

